Sparse imaging using improved OMP technique in FD-MIMO radar for target off the grid

The frequency diverse multiple-input multiple-output (FD-MIMO) radar has the potential to achieve high range and angle resolution by combining multiple frequency signals into a wideband signal. Moreover, higher resolution can be obtained by exploiting the sparsity of the target based on compressed sensing (CS) theory. However, traditional CS-based imaging methods would be severely affected when off-grid scatterers exist. To overcome the problem stated above, this paper proposes a sparse imaging method to deal with off-grid target in FD-MIMO radar using improved orthogonal matching pursuit (OMP) technique both in the range and angle dimension. Firstly, the off-grid simultaneous OMP (OG-SOMP) method is proposed for range compression, then for angle compression, the off-grid OMP (OG-OMP) method is implemented to each non-zero range profile. Simulation results are provided to demonstrate the performance improvement of the proposed method.